frequency

American  

[free-kwuhn-see] / ˈfri kwən si /

noun

frequencies plural

1. Also frequence. the state or fact of being frequent; frequent occurrence.

   We are alarmed by the frequency of fires in the neighborhood.

   Synonyms:

   recurrence, repetition, regularity

2. rate of occurrence.

   The doctor has increased the frequency of his visits.

3. Physics.

   1. the number of periods or regularly occurring events of any given kind in unit of time, usually in one second.

   2. the number of cycles or completed alternations per unit time of a wave or oscillation. F; freq.

4. Mathematics. the number of times a value recurs in a unit change of the independent variable of a given function.

5. Statistics. the number of items occurring in a given category.

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frequency British  

/ ˈfriːkwənsɪ /

noun

1. the state of being frequent; frequent occurrence

2. the number of times that an event occurs within a given period; rate of recurrence

3.  ν.   f.  physics the number of times that a periodic function or vibration repeats itself in a specified time, often 1 second. It is usually measured in hertz

4. statistics

   1. the number of individuals in a class ( absolute frequency )

   2. the ratio of this number to the total number of individuals under survey ( relative frequency )

5. ecology

   1. the number of individuals of a species within a given area

   2. the percentage of quadrats that contains individuals of a species

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frequency Scientific  

/ frē′kwən-sē /

1. Physics The rate at which a repeating event occurs, such as the full cycle of a wave. Frequencies are usually measured in hertz.

2. Physics Compare amplitude See also period

3. Mathematics The ratio of the number of occurrences of some event to the number of opportunities for its occurrence.

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frequency Cultural  

1. In physics, the number of crests of a wave that move past a given point in a given unit of time. The most common unit of frequency is the hertz (Hz), corresponding to one crest per second. The frequency of a wave can be calculated by dividing the speed of the wave by the wavelength. Thus, in the electromagnetic spectrum, the wavelengths decrease as the frequencies increase, and vice versa.

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Other Word Forms

Derived Forms

• nonfrequence
  noun
• nonfrequency
  noun
• overfrequency
  noun
• underfrequency
  noun

Inflected Forms

Nouns

• frequencies
  plural

Etymology

Origin of frequency

First recorded in 1545–55, frequency is from the Latin word frequentia assembly, multitude, crowd. See frequent, -cy

Explanation

Frequency measures how often things repeat over time. City buses often reach stops at a frequency of every 15 minutes, unless it's snowing or raining really hard. In that case, the frequency will slow. You probably know the word frequent, a synonym for often. So, it is tempting to think frequency describes something that happens often. However, this isn't true: frequency describes any rate of time at which something repeats. For example, from Earth, Halley's Comet is visible at a frequency of 76 years — it's not frequent, but it is on schedule.

Example Sentences

See Examples For:

frequency frequencies

It adds that climate change is intensifying wildfires and increasing their frequency.

From BBC ● Jul. 27, 2026

Climate change is increasing the frequency and severity of disturbances affecting old-growth forests, including drought and extreme wildfire.

From Science Daily ● Jul. 26, 2026

Reducing the frequency of required financial reports strikes at the heart of its design.

From The Wall Street Journal ● Jul. 26, 2026

Scientists say human-induced climate change is increasing the frequency and intensity of extreme heat events in Japan and elsewhere.

From Barron's ● Jul. 22, 2026

If a star is moving toward Earth, the light is crushed and has a higher frequency than normal; it is shifted toward the blue end of the spectrum, blueshifted.

From "Zero: The Biography of a Dangerous Idea" by Charles Seife

Only two people had better than average hearing at certain low frequencies.

From Science Daily ● Jul. 19, 2026

Kossuth's frequencies were instead broadcasting classical music station Bartok Radio, according to AFP news agency.

From BBC ● Jul. 7, 2026

The new aircraft deliveries will support higher frequencies, the restoration of suspended routes and entry into new destinations across Asia and Europe, the analysts add.

From The Wall Street Journal ● Jul. 1, 2026

Spectrum are the frequencies over which wireless calls and data travel.

From Barron's ● Jun. 30, 2026

And you can put different amounts of water in different glasses and they make different notes because they have what are called different resonant frequencies, and you can play a tune like Three Blind Mice.

From "The Curious Incident of the Dog in the Night-Time" by Mark Haddon

Related Words

• density
• number
• prevalence
• recurrence
• regularity
• repetition